URBANA, Ill. — Following decades of decline, even fewer birds will darken North American skies by the end of the century, according to a new analysis by scientists at the University of Illinois Urbana-Champaign. Their study is the first to examine the long-term effects of climate change on the abundance and diversity of bird groups across the continent as a whole while accounting for additional factors that put birds at risk, such as pesticides, pollution, land use change, and habitat loss.  

“Many studies try to attribute causes like climate or land use change to bird population decline based on field-level observation. However, there has been no large-scale statistical analysis that puts together historical data on biodiversity and climate for North America,” said study co-author Luoye Chen, an assistant professor at the Hong Kong University of Science and Technology (Guangzhou). Chen completed the research during his doctoral program in the Department of Agricultural and Consumer Economics, part of the College of Agricultural, Consumer and Environmental Sciences at Illinois.  

The study relies on data from the North American Breeding Bird Survey, which gathers detailed field observations of more than 400 bird species across the continent each spring. Analyzing bird population trends between 1980 and 2015 together with climate data from the same timeframe, the researchers show a modest but significant dip in the number and diversity of birds overall and a larger drop for specialist and migratory groups. The analysis also projects scenarios for the years 2095 to 2099, with still greater declines.

Read the full release from College of Agricultural, Consumer and Environmental Sciences.